National Geographic Survey Tries To Make Sense Of Smell

WASHINGTON — Women usually have a more acute sense of smell than men, allergies do not impair a person's ability to identify odors and, like roses, vivid memories lose their scent when they get old.

In addition, many Americans are ''odor blind'' to two common scents -- the smell of musk and the smell of sweat.

In addition, many Americans are ''odor blind'' to two common scents -- the smell of musk and the smell of sweat.

Those are some of the results of National Geographic Magazine's 1.5- million-participant odor survey, researchers said last week.

The research was designed by scientists from the Monell Chemical Senses Center in Philadelphia, an institution devoted to the study of taste and smell. It was based on reader responses to a questionnaire about six scratch- and-sniff panels the magazine published in its September 1986 issue. The six scents -- identified in next month's issue -- were androstenone (sweat), isoamyl acetate (banana), Galaxolide (musk), eugenol (cloves), mercaptans (a foul smell added to natural gas) and rose.

Readers were asked seven questions about each scent -- such as ''Did

it evoke a vivid memory?'' or ''Would you eat something that smelled like this?'' They also were asked to select the word that best described the odor (fruity, floral, spicey, etc.). And they were asked for information about themselves, such as age and sex, whether they were pregnant, smoked or had allergies and where they worked.

Of the magazine's 11 million subscribers, 1.5 million mailed in questionnaires, researchers said, making it one of the largest scientific experiments ever conducted.

Preliminary results appear in the October issue of the magazine and were described last week at a press conference at the National Geographic Society in Washington. They were based on a random selection of 26,200 replies from readers in the United States and all 100,000 responses from abroad.

Fully half the responses in this sample were from readers who said they were able to smell all six odor blocks. Only about one percent said they couldn't smell three or more.

About 35 percent could not detect the odor of sweat and 29 percent could not smell musk. These numbers are significant, considering, for example, that only 2 percent of Americans are colorblind.

The tendency of odors to evoke vivid memories and deep feelings is not well understood, although scientists have known that the sense of smell is intimately tied to the part of the brain most involved with memory and emotion.

The survey indicated that the stronger an odor, the likelier it is to evoke a vivid memory, and that extremely pleasant and extremely unpleasant odors are most likely to stir recollections.

But odor-evoked memories gradually become less frequent with age, the survey indicated.

Other findings:

-- Contrary to their self-ratings, factory workers can detect odors better than people who work outdoors. Those who don't work at all rank below both other groups.

-- Nearly two out of three people have suffered at least a temporary loss of smell -- even if only from a cold or sinus infection -- but only 1.2 percent have a permanent loss.

-- Women usually can smell more acutely than men, but pregnant women may experience a diminished sense of smell.

-- Although odor-detection ability remains near youthful levels well into the 60s, the ability to identify smells and the sensitivity to odor intensity starts declining, slightly and slowly, in the 20s.

-- Smokers found the smell of mercaptans more pleasant than non-smokers did, and older residents showed a surprising lack of negative reaction to this scent.

The society said it has spent $1 million on the survey and has allocated $200,000 more to tabulate the rest of the returns on computer tapes. The data will be made available to outside researchers.

In addition to responding to the multiple-choice questions on the survey, many readers sent in their own comments.

One man said his wife could ''smell beer over the telephone.'' A pregnant woman said odors seem to trigger much of her nausea. Another reader said the smell of kerosene brings back memories of ''reading by a kerosene light, the feeling of closeness and safety and the shadows cast on the walls, the laughter of a grandmother dead 30 years.''

A woman wrote, ''After my husband died, I would go into his closet and hug his suits, because they smelled of his own body odor, slight cigarette smell, and aftershave. I'd stand there, hugging his clothes, making believe, close my eyes and cry.''

One person mailed in the survey form after allowing a family cat to smell the musk block. The animal left tooth marks in the survey form, a response the researchers concluded -- or assumed -- meant that it found the scent disagreeable.